#!/usr/bin/env node
const mysql = require('mysql2/promise'),
      log = console.log;

let con = mysql.createPool({
  host: '127.0.0.1',
  user: 'root',
  password: 'ddd',
  database: 'test'
});
getAreas();
async function addAreas(areaName){
  const sql =`insert into areas(area_name) values('${areaName}')`;
  let [rows] = await con.execute(sql);
  return rows;
}
async function delArea(areaName){
  const sql = `delete from areas where area_name='${areaName}'`;
  let [rows] = await con.execute(sql);
  return rows;
}
async function updateAreas(oldName, newName){
  const sql = `update areas set area_name = '${newName}' where area_name='${oldName}'`;
  let [rows] = await con.execute(sql);
  return rows;
}

async function getAreas(){
  const sql ='select * from areas';
  let [rows] = await con.execute(sql);
  return rows;
}

(async function(){
  //await addAreas('英国');
  //updateAreas('英国', '大不列颠');
  await delArea('大不列颠');
  log(await getAreas());  
})();
